I grew the Purple Heron from seed and love this little gem. Some plants are growing in full sun/poor soil and others are growing in part shade/rich soil. All are doing very well - nice mounds of foliage and good flower flushes. No issues with powdery mildew which may have to do with our cooler summers than those in Ontario, so being in Massachussets? you may not have that problem as well if you are close to the ocean.

The ones in full sun have also reseeded and again are coming true. I will be keeping them all to myself as they are quite the little gems. :O)

I am not disappointed with my 'Midnight Reiter', which I purchaced about four years ago.

It is a smallish geranium, standing around ten inches tall before bloom and a little over a foot tall while in bloom. A very tidy habit; strong, upright grower that does not flop. The flowers are large and a pretty blue color. The stems are reddish. The foliage is a nice 'purple' color, sometimes with a hint of dark green at the center when the foliage is mature.

Yes, the plant will get some powdery mildew. But I haven't found it to be severe (not like Geranium 'Splish Splash' who never seems to be a season without it. I don't doubt it even has it when it is dormant in winter and under the ground). I have found the mildew to, luckily, crop up on the plant after it blooms. Just cut it down and new foliage will grow.

This plant also sets good seed. I am not much of a seed collector or grower, but it is very easy to grow seed from 'Midnight Reiter'. The first year I had it I didn't know to cut it down after it bloomed (for the mildew). Seeds formed, so I collected a few and just stuck them in the ground. They came up wonderfully! They haven't bloomed yet, but the foliage on the seedlings look just like that of their parent. Last year I didn't get around to cutting it down, so again the plant set seed. I cut it down and just 'shook' out the seeds. Little seedlings are comming up all over that area, which is fine with me.

it is a first I hear geraniums get mildue on them and I am growing them in hundreds, love those plants. I love midnight reiter, now I have seen Dark reiter and want it too. Many of the forms I grew from seed and many of hybrids will come true.
Mine in shade, as I do not have sun. Right now pyrenaicums are in full bloom and Nimbus started and oxonianum Claridge Druse, and sanguineum. Tiny Monster is sending couple of flowers and several pratense forms are getting in the business of blooming. Wlassovianum, thungbergii and yoshinoi will come later in the summer, this year I got tons from seeds of Confetti and Jester Jacket so lots of colored foliage.
Just germinated lots of seeds from Plant World seeds- geranium soboliferum, shikokianum, Purple Haze which is absolute stunner early spring...

Thanks for these replies. Much as I loved the look of it, I am thinking this may not do well for me. Geraniums are so variable. The ones that like full sun and dry-ish soil don't do well for me. I have lots of shade and deep moist soil. Too bad--this is a beauty.

Must add that I am surprised to hear about mildew on geraniums. I have never seen any on the ones I've grown.

Gosh, no mildew on my Midnight Reiter here...I'd have thought with our cloud cover and fog if a plant were going to mildew I'd find it on mine :) I bought mine as two immature seedlings too young to ship (and they didn't, I picked them up) and I'm not going to admit what I paid many years ago, way too much.

I find the seedlings they produce variable though...a few true purple black like the parents (maybe 25%), many purple fading to green over time so more like Victor Reiter coloring, and a few plain green - all with the typical blue flowers.

I was having a problem with stems appearing almost broken close to the ground - several after dark trips with a flashlight finally revealed confused rhododendron weevils munching on the leaf and flower stems, about the last insect I suspected....no wonder slug bait wasn't deterring them.

I bought it this year for the third time...first time it fizzled out after a year or two, last year it just died.
This year it has actually grown since I bought it about 6 weeks ago. It's getting a mix of sun and shade, but I do consider the garden it is in as full sun. I've got lots of geraniums: Rozanne, Jolly Bee, "Johnson's blue improved," and a bunch of others, and have never, ever had mildew...

My Midnight Reiter fizzled and died. I had it planted in my main garden in full morning and dappled shade from 1 pm to sundown. It just never seemed like a healthy plant.
I have other geraniums doing great, no mildew....not like the beebalm. Now that is bad!

Not sure it is relevant here, but I've found both G. maculatum 'Elizabeth Ann' & G. 'Orkney Cherry' are very mildew resistant. Nice dark foliage on both, though they have chocolate-y tones more than purple like Midnight Reiter. A GW bud sent me the OC last year and so far I'm totally happy with it ;-)
CMK

Geranium pratense NEARLY ALWAYS gets mildew, they just belong together. All the dark-leaved varieties proved to be very weak plants here, two actually DIED from mildew!. My sorrow was very short. The colour of the leaves was identical to the colour of my soil, which made the plants invisible anyway. The only two pratense varieties worth growing are Violaceum Plenum and Summer Skies(misleading name, pinkish). They stand up nicely and regrow after cutting down.

Just want to give a word of praise for G. maculatum 'Elizabeth Ann'. It is a stunning, easy care bronze-leaved selection with no disease issues. I much prefer it to 'Espresso' (which has equally wonderful foliage) because it is taller with larger blooms. Flower color on 'Elizabeth Ann' is a light almost pure lavender with just a hint of pink, whereas 'Espresso' runs more on the light pink side. A clump of 'Elizabeth Ann' is spectacular in full bloom and the foliage is surprisingly visible in shade. I am hoping to find a few bronze leaf seedlings around my plants in the future.

I have not tried a dark-leaved clone or strain of G. pratense, but I am now on year 2 with 'Violaceum Plenum'. It has been very slow to establish for me but I was pleased to note the other day that it is sending up two bloom spikes. No mildew last year or so far this year. I recently added 'Elizabeth Yeo' and 'Mrs Kendall Clark', so I will see in the future how they perform for me.